As part of the assignment, the influence of cooling rates and annealing temperatures on the cold workability of EN AW-7075 alloy is presented and analyzed. The analyses were carried out on indirect extruded rods with a diameter of 11 mm, which are specifically used in the respective company for the production of high-strength products, carabiners. Due to the high mechanical properties achieved by the transformation and fast natural aging process of the alloy, further cold transformation is limited. To avoid this, the rods were soft annealed after the extrusion process and cooled in a controlled manner in a laboratory furnace with predefined parameters. This amplifies the reduction of mechanical properties, which are necessary to ensure the transformation ability of the material. Tight tolerance zones and geometrically satisfactory cross-sections are achieved by deformation drawing through the hollow tool. For the purposes of the study, deformation rates of 2 % and 6 % were chosen. A comparison of measured mechanical properties, both thermal and mechanical, provides a detailed insight into the material’s evolution through the process chain. The final test, i.e. the bending test, was carried out in an industrial process, after which the annealing time and temperature, the cooling rates and the rate of deformation are defined. After completing all stages of the processes chain and heat treatments, the samples were examined on a Scanning Electron Microscope (SEM) with EBSD analysis. Various analyzes have been carried out to identify the resulting differences and changes in mechanical properties. A detailed analysis of the textural components (Brass, Copper, Cube, Goss, P and S) by evaluation the ODF and Pole figure images allowed to explain the variations of mechanical properties of the material. The definition of the material’s ability to be further transformed was given by the Schmid factor values. The degree of recrystallisation of the grains was checked by GAM analysis.
By evaluating the results, we can give the opinion that all the thermal and deformation treatments analyzed in the master's thesis are suitable for this kind of cold transformation into a preform for the production of carabiners.
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